Pawl and ratchet mechanism for alarm clock timer sleep switch cam

ABSTRACT

A sleep switch movement for a clock timer wherein a unique pawl and ratchet mechanism is provided for driving a sleep switch cam. A pawl is counterweighted for urging it into contact with teeth on the sleep cam. The pawl is indexed one increment each minute by a drive mechanism; however, a cam shaft having two flat surfaces is positioned in engagement with the pawl for permitting the pawl to drive teeth on the sleep cam only twice for each revolution of the cam or once every five minutes.

United States Patent 1191 11] 3,725,615 Boyles et al. 1 Apr. 3, 1973 54]PAWL AND RATCHET MECHANISM 3,136,114 6/1964 Jauch ..5s/39.5 x FOR ALARMCLOCK TIMER SLEEP 3,062,931 11/1962 Boyles ...200/38 FB SWITCH CAM3,432,625 3/1969 Polonsky et al. ..200/35 A 3,475,899 11/1969 Boyles..200/38 FB X [75] Inventors: Robert L. Boyles, Wayland; Samuel PolonskyMedway both of Mass Primary Examiner-J. R. Scott [73] Assignee: GeneralElectric Company, Bridge- AtwmeyLawrence R. PIO t 6 port, Conn. 22Filed: Apr. 7, 1972 [57] ABSTRACT [21] APPL No: 242,032 A sleep switchmovement for a clock timer wherein a unique pawl and ratchet mechanismis provided for driving a sleep switch cam. A pawl is counterweighted[52] [1.8. CI. ..200/38 FB, 200/35 A for urging it intocomact with teethon the sleep cam [51] f i g 7/08 The pawl is indexed one increment eachminute by a [58] he of Seam 86/ Z drive mechanism; however, a cam shafthaving two 1 flat surfaces is positioned in engagement with the pawl[56] References Cited for permitting the pawl to drive teeth on thesleep cam only twice for each revolution of the cam or once UNITEDSTATES PATENTS every fiv minutes. 2,505,573 4/1950 'Prophet ..200/38 FA9 Claims, 9 Drawing Figures 3,033,948 5/1962 Boyles ..200/38 FBAPMENTEUAPM 1915sszuw 3 UP 5' PATE T DA I815 3.725.615

sum 5 0F 5 I a Alli ll]. w

PAWL AND RATCHET MECHANISM FOR ALARM CLOCK TIMER SLEEP SWITCH CAMBACKGROUND OF THE INVENTION This invention relates to a clock timer, andmore particularly, to an improved sleep switch movement for a clocktimer which may be readily and reliably operated to close a switch for apredetermined time interval.

It is found highly desirable in the manufacture of clock timers toprovide a mechanism for manually turning on a radio at bed time and thenautomatically turning off the radio a short time thereafter while theuser goes to sleep. Known sleep switch timers of this type are shown ina prior U.S. Pat. No. 3,475,899 to Robert L. Boyles dated Nov. 4, 1969.As shown in the patent a rotatable sector gear 150 is moved intoengagement with aconstantly rotating clock gear 160 through the use of afriction clutch assembly 162, 158, 164, and 166 which is positionedbetween the continuously rotatable gear 160 and the sector gear 150. Thesleep sector gear 150 rotates with the clock gears 160 and 158 until thesector gear is driven out of mesh with the gear 158 to thereby shut offthe radio by opening a switch 57-59 which is actuated by the sectorgear.

, Our invention is concerned with such a sleep switch movement, and moreparticularly, to a unique pawl and ratchet drive mechanism for a sleepgear which does not require the use of a friction clutch mechanism forconnecting the sleep gear to a continuously rotated timing gear.

In our co-pending application, Ser. No. 196,479, filed Nov. 8, 1971, andassigned to the same assignee as the present invention, there isdisclosed a digital clock including a mechanism for driving minutes,tens of minutes, hours and tens of hours display indicators for adigital clock. This invention is also concerned with the addition of areliable sleep switch mechanism to such a digital clock.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of ourinvention to provide an improved reliable sleep switch mechanism for aclock timer having relatively few parts, and it is also an object of ourinvention to provide a sleep switch mechanism which may be readilycombined with a digital clock of the type disclosed in theabove-mentioned co-pending application.

In accordance with one of the aspects of this invention, an alarm clocktimer includes a switch having an open and a closed position and atiming motor. A sleep cam is operably connected to the switch forclosing the switch for a predetermined time interval, and a knob orother manually operable means is formed integrally with or connected tothe sleep cam for manually moving the sleep cam to open or close theswitch. Ratchet teeth are formed on the sleep cam for permitting thesleep cam to be moved from a switch closed position to a switch openposition by the timing motor. To achieve this, a pawl lever ispositioned in the alarm clock timer mechanism and means is provided formoving the pawl lever into engagement with the ratchet teeth when it isdesired to move the sleep cam in a direction for opening the switch. Adrive mechanism is operably connected to the timing motor for moving thepawl lever back and forth to incrementally move the sleep cam as afunction of time in order to open the switch at the end of the timeinterval.

With this construction, the sleep cam is not continuously rotated by thetiming motor when it is being operated by the timing motor, but is onlyincrementally moved on one of the strokes of the pawl lever. Thus, itonly places a load on the timing motor on one of the strokes of the pawllever, and accordingly, during the return stroke of the pawl lever themotor will have available torque to drive other mechanisms.

In addition, with the use of a pawl lever for driving a sleep camthrough ratchet teeth there is no need for a friction clutch assemblybetween the sleep cam and a continuously rotated gear.

BRIEF DESCRIPTION OF THE DRAWING Other objects and attendant advantagesof the invention will be apparent from the following description takenin connection with the accompanying drawing in which:

FIG. 1 is a front elevational view of a digital alarm clock timerconstructed in accordance with our invention;

FIG. 2 is a fragmentary exploded front perspective view of a portion ofthe switch operating and sleep cam mechanism of the digital clock shownin FIG. 1;

FIG. 3 is a fragmentary exploded front perspective view generallysimilar to FIG. 2 with many of the parts of the display mechanism of theclock removed for purposes of illustration, the parts of our sleepswitch movement being shown in a position wherein the parts are underthe control of an alarm shut-off cam which overrides a sleep cam to movethe switch to an open position to shut off the alarm;

FIG. 4 is a fragmentary exploded front perspective view similar to FIG.3 showing the parts under the control of an alarm cam with the alarm camin a position to hold a switch actuating lever and the switch in an openposition;

FIG. 5 is a fragmentary exploded front perspective view generallysimilar to FIG. 4 showing the parts under the control of an alarm timecam wherein the alarm time cam has functioned to close the switch at thealarm time;

FIG. 6 is a fragmentary exploded front perspective view generallysimilar to FIG. 5 with the parts under the control of our sleep cammovement for closing the switch for a predetermined short time interval;

FIG. 7 is a fragmentary exploded front perspective view generallysimilar to FIG. 6 showing a plural position lever in an ON notch on thesleep cam and showing our sleep drive pawl lever on a smooth portion ofthe sleep cam;

a sleep cam for moving the sleep cam to a switch open position; and

FIG. 9 is a fragmentary front elevational viewgenerally similar toFIG. 8showing the pawl lever held out of mesh with the sleep cam forpermitting the sleep DESCRIPTION OF THE PREFERRED EMBODIMENT Referringnow to the drawing and first particularly to FIGS. 1 and 2, there isshown a digital clock which includes our unique sleep cam mechanism. Theclock includes four numeral display indicators 2, 4, 6 and 8 whichindicate minutes, tens of minutes, hours and tens of hours,respectively. As shown in FIG. 2, portions of the display indicators areidentified by reference numerals 30, 32, 34, 46, 48 and 50, portions ofthe cams and other mechanism for driving the display indicators areshown by reference numerals52, 54, 56, 74 and 72, and our improved alarmmechanism is generally identified by reference numeral 200.

The details of the digital display indicators 2, 4, 6 and 8 and thedetails of the mechanism for indexing and driving the minutes, tens ofminutes, and hours cams do not form a part of this invention and aredescribed and illustrated in greater detail in our co-pendingapplication, Ser. No. 196,479, filed Nov. 8, 1971, and a copendingapplication of Robert L. Boyles, Ser. No. 105,854, both assigned to thesame assignee as the present invention.

As shown in FIG. 1, the display indicators 2, 4' and 6 include a commonfront plate 24 which may be formed of a sheet of plastic that may bereadily slotted or blocked out to reveal three clear numeral 8s, one foreach of the display indicators 2, 4 and 6. With particular reference toFIG. 2, each of the display indicators 2, 4 and 6' includes a verticallymovable shutter 30,32 and 34, respectively, for selectively blocking outone or more of the horizontal indicator bars 10, 12 and 14. It can beappreciated that all of the horizontal bars should be blocked out fordisplaying a numeral 1 while only the central bar 12 should be blockedout for displaying the numeral 0. To achieve this, a plurality of opaqueshutter bars 36, 38 and 40 may be painted or otherwise formed on thevertically movable shutter members 30, 32 and 34 for blocking out theappropriate horizontal indicator bars.

With particular reference to FIG. 2, horizontally slidable shutters 46and 48 and 50 are positioned behind the vertically slidable shutters forselectively obstructing the vertical bars l6, 18, 20 and 22 of the a camfollower 62 in order to appropriately position the vertically movableshutters 30, 32 and 34. A cam groove (not shown) is also formed in therear face of the rotatable cams 52, 54 and 56 for moving the horizontalshutters 46, 48 and 50 back and forth behind the vertical shutters 30,32 and 34. With this construction, when the cams 52, 54 and 56 arerotated in a clockwise direction as illustrated in FIG. 2, the front camgroove and cam follower causes the vertical sliders to move upwardly anddownwardly with respect to the slotted numeral 8 numbers, and the rearcam track causes the horizontal shutters 46, 48 and 50 to be moved tothe right and left behind the vertical shutters slotted FIG. 8 numeralsof the display indicators 2, 4

and 6. It can be appreciated that the upper left vertical bar 18 shouldbe blocked out to display numerals l, 2 and 3 while it would beunobstructed to display the numerals 6, 8 and 9, for example.

It can be readily appreciated that in order to display a particularnumeral the vertical shutter has to be moved to one position while thehorizontally movable shutter is required to be moved to a differentposition. For example, in order to display the numeral 2 as shown inFIG. 1, the vertically movable shutter has to be moved to leave all ofthe horizontal bars l0, l2 and unobstructed. In a similar manner, thehorizontally movable shutter has to be moved to block out only the lowerright and upper left vertical indicator bars 20 and 18, respectively.

With reference to FIG. 2, two-faced-rotatable cams 52, 54 and 56 areprovided for moving the vertical shutters '30, 32 and 34, respectively,and the horizontal shutters 46, 4 8 and 50,; respectively. The frontfaces of each of the cams include a cam groove 60 for receiving and'theslotted numeral 8.

The horizontal and vertical shutters and the cam groove arrangement formoving them are illustrated and described in greater detail in theaforementioned co-pending application of Robert L. Boyles, assigned tothe same assignee as the present invention.

MINUTES AND TENS OF MINUTES CAM INDEXING AND DRIVE ARRANGEMENT Amechanism is positioned between the minutes and tens cams 52 and 54 forindexing the minutes cam once every minute and for simultaneouslyindexing the tens cam one increment at the instant that the minutes camis being indexed a tenth increment, so that the minutes cam and the tenscam are simultaneously indexed to the next succeeding numbers when theunits cam is being moved to its-tenth increment. To achieve this,

special cam teeth and 82 are integrally formed on the outer periphery ofthe cams 52 and S4 for cooperating with a pawl lever 84 which ispositioned between the cams. As shown more particularly in FIG. 2, theindexing mechanism includes a drive lever 86 which is pivotally mountedon the digital clock between the units and tens cams 52 and 54.

An arrangement for oscillating the drive lever '86 to provide a rapidclockwise advance stroke of about 5 seconds duration and a slower returnstroke once per minute is shown in FIG. 2. To accomplish this, the drivelever 86 is provided with cam surfaces for cooperating with an eccentricdrive roller 106 mounted on a gear 108 that is rotated at one revolutionper minute by a pinion 110 of a synchronous electric motor 111. The gear108 and its eccentric roller 106 are rotated in a clockwise directionand the roller 106 abuts a cam surface to pivot the upper portion of thedrive lever 86 to the right about its lower pivot 88 to move a unitspawl 112 of the pawl lever 84 to the right. With reference to FIG. 2,the pawl 112 moves against a tooth of the units cam 52 to move the unitscam 52 one increment to thereby actuate the units display indicator 2 todisplay a next succeeding numeral. Continued rotation of the eccentricroller 106 moves the roller into contact with a return stroke camsurface to move the drive lever 86 and the pawl lever 84 to the left asshown in FIG. 2.:

The pawl lever 84 is uniquely shaped, weighted and pivoted so that therelatively small pawl lever 84 may reliably index both the units cam 52and the tens cam 54. The pawl lever 84 includes a central portion 116dexing the tens cam 54. As shown more particularly in FIG. 2, the pawl84 is uniquely weighted by a counterweighted portion 113 in the vicinityof the units pawl 112 so that the pawl 112 gently rests on the units cam52. In this position, it can be appreciated that the tens pawl 120 islocated above the teeth 82 on the tens cam 54. Thus, during nine of theten incremental movements of the pawl lever 84, the tens pawl 120 clearsthe teeth 82 on the tens cam 54, and consequently, the tens cam 54remains stationary.

During the tenth incremental movement of the drive lever 86 themechanism indexes both the units cam 52 and the tens cam 54simultaneously so that the succeeding numerals will simultaneouslyappear at the display indicators 2 and 4. To accomplish this the tenthtooth on the units cam is made much higher than the other nine teeth ofthe units cam which correspond to numerals 1 thru 9. This causes theleft tens pawl 120 to be moved downwardly to engage one of the teeth 82on the tens cam. Accordingly, the units pawl l12is in engagement withthe high tooth on the units cam, and tens pawl 120 is in engagement withone of the teeth on the tens cam 54, and further rotation of theeccentric roller 106 against the drive lever 86 will cause the drivelever and the pawl lever 84 to be moved to the right to index both theunits cam 52 and the tens cam 54 one increment. It can be appreciatedthat this movement of both cams occurs simultaneously, and thus, aperson viewing the digital clock will observe a simultaneous change inboth the-units and the tens numerals which appear on display indicators2 and 4, respectively. It can also be appreciated that withthismechanism the units cam 52 will bedriven at one revolution every tenminutes in order to display numerals from 0 thru 9 and the tens cam 54will be driven at one revolution each hour.

The digital display structure and the mechanism for driving and indexingthe display indicators so far described is illustrated and described infuller detail in our aforementioned co-pending application, Ser. No.l96,479,filed Nov. 8, 1971.

I ALARM MECHANISM A switch and alarm mechanism is incorporated withthe'digital clock thus far described so that the clock may be utilizedas a radio alarm timer for automatically turning a radio on at a presettime. The alarm mechanism is generally designated by reference numeral200 in FIG. 2, and with particular reference to FIGS. 3, 4 and 6, it canbe seen that a switch 201 for the alarm mechanism is positionedrearwardly of mounting plate 100.

The switch 201 includes a pair of switch blades 202 and 204 having apair of switch contacts 206 and 208 mounted at their free end portions.Rear switch blade 202 is somewhat longer than the front switch blade 204and is formed of spring material for normally biasing the-rear switchblade forwardly to hold the switch contacts in a closed position. Theswitch blades may be mounted on a conventional switch block member 210which may be connected to the rear plate 100 of the digital clock by anysuitable securing means. As shown, the switch is mounted so that theswitch blades 202 and 204 are arranged in planes which are generallyparallel to the base plate 100. With this arrangement, rearward ortransverse movement of the free end portion of the switch blade 202 willopen the switch contacts.

An elongated switch actuating lever 212 is positioned between the rearswitch blade 202 and the base plate 100 for opening or closing theswitch in response to movement of an alaim time cam mechanism 214, aSLEEP, ON or OFF cam mechanism 215 or an alarm shut-off cam mechanism216. It can be appreciated that rearward transverse movement of theelongated switch actuating lever 212 will cause the lower end portion217 of the lever to abut the front surface of switch blade 202 andfurther rearward movement of the lever will cause the switch blade 202to be moved far enough rearwardly to open the switch contacts 206 and208, as shown more particularly in FIG. 3.

The alarm cam mechanism for allowing the elongated switch actuatinglever 212 to be moved transversely forwardly at a preset alarm time toclose the switch contacts 206 and 208 to thereby turn on a radio orother alarm at a preset time will now be more particularly described.Basically, the alarm cam mechanism includes two coaxially mounted gears218 and 219 which .are provided with interacting cams 220 and 222,

respectively, for causing relative axial movement of the gears at apreset time for actuating the switch 206 and 208.

As shown more particularly in FIGS. 2 and 3, cam gear 218 functions asan alarm time cam and is driven at one revolution every twelve hours bya pinion gear 224 which may be integrally formed with the tens ofminutes cam gear 54. Thus, the alarm time cam gear 218 is provided witha sufficient number of teeth on its outer periphery to achieve asuitable gear reduction from the tens of minutes pinion 224 so that thealarm time cam gear 218 will be driven at one revolution every 12 hours.

The alarm cam 220 is fixed to its gear 218 and their common shaft 242 inany suitable manner. As shown in FIG. 3 the cam 220 is generallycircular in shape with a cutout or notch 226 which forms the operableportion.

As shown more particularly in FIG. 3, the alarm set cam gear 219 isfixed to a shaft 230 which extends forwardly and rearwardly therefrom,and a knob 232 may be fixed to forward end of shaft 230 for manuallyrotating the alarm set cam 222 to any desired alarm time.

The alarm time cam 218, 220 and the alarm set cam 219, 222 are supportedin coaxial relationship with respect to each other on the digital alarmclock by providing shaft 242 of the alarm time cam with a relativelysmall diameter so that it extends into a hollow end portion of shaft 230of the alarm set cam. As shown more particularly in FIGS. 8 and 9, theshaft 242 extends rearwardly through an aperture 244 which is formed inthe mounting plate 100 and as shown in FIG. 2 the shaft 230 extendsforwardly through an aperture 246 which is formed in a front plate 248for supporting the alarm time cam and the alarm set cam on the digitalclock.

In operation, if it is desired to have the alarm ring at I 6 oclock inthe morning, the operator rotates knob 232, the alarm time indicatingdisk 234, and hence, the alarm set cam 219 to the appropriate 6 o'clockposition as indicated in FIG. 1. The spring force of the switch blade202. urges the front face-of cam 220 into contact with the cam finger222 on the alarm set cam 219,- and thus, the forward cam surface of camfinger 222 will ride on the forward face of cam 220 as the cam 220 iscontinuously rotated by the gear 218 and pinion 224 of the tens ofminutes cam.

At 6 oclock in the morning the cam finger 222 will become aligned withthe cam notch 226 which is formed in cam 220 and the switch blade 202will rapidly force the continuously rotated gear 218 axially toward thegear 222 as the finger 228 moves into the cam notch 226 at the alarmtime, as shown in FIGS. 5, 9 and 10. Naturally, during this movement theswitch blade 202 will also move forwardly to close switch contacts 206,208.

The alarm mechanism so far described is illustrated and described ingreater detail in our co-pending application, Ser. No. 241,963, filedApr. 7, 1972.

As described in the above-mentioned co-pending application, a WAKE-NOWAKE alarm shut-off cam lever mechanism 216, 254 is provided for movingthe alarm time cam gear 218, 220 rearwardly to position finger 222 onthe front surface of cam 220. As shown more particularly in FIG. 3, themechanism includes a bifurcated lever 254 which is pivoted by tabs 256and 258 to the mounting plate 100 of our digital clock.

One downwardly extending arm 260 of the lever includes a U-shaped slot261 for receiving an annular groove 262 which is formed on the shaft,portion 242 of the alarm time cam. With this construction, the lever 254is loosely held to the alarm time cam gear 218. The other left arm 264of the lever 254 extends downwardly into a position to be actuated bythe WAKE-NO WAKE cam 216. a

With the use of the manual reset cam system disclosed in our co-pendingapplication Ser. No. 241,963, after the switch 206, 208 has been movedto its closed position as shown in FIGS. 5, 9 and 10, at 6 os clock inthe morning in the above-mentioned example, and it is desired to turnoff the radio or alarm, the radio or alarm switch 206, 208 may bereadily moved to the open position illustrated in FIG. 3 by rotating theWAKE-NO WAKE cam 216 clockwise from the position illustrated in FIG. tothe position illustrated in FIG. 3. During this movement, the cam 216moves arm 264 toward the base plate 100 to thereby simultaneously movearm 260 and the alarm time cam 218 including its shaft 242 rearwardly toopen switch contacts 206, 208. This movement for opening the switch alsosimultaneously manually resets the cam finger 222 on top of the frontsurface of cam 220.

ON-OFF-SLEEP A manually settable SLEEP-ON-OFF cam mechanism 215 isarranged to control lever 268 and switch actuating lever 212. From the.preceding description of the alarm cam mechanism 218 and 219, it can beappreciated that the elongated switch actuating lever 212 serves as anintermediary between the end of shaft 242 and switch blade 202; i.e.,when the end of shaft 242 is moved forwardly the lower portion of lever212 and switch blade 202 is moved forwardly, and when the shaft 242 ismoved rearwardly actuator 212 and the switch blade 202 are movedrearwardly.

The switch actuating lever 212 isuniquely shaped and positioned so thatit may be manually pushed downwardly at any time to close the switchwithout disturbing the position of shaft 242. To achieve this, an upperend portion 266 is pivoted to a plural position lever 268 which in turnis arranged to be actuated by the ON-OFF-SLEEP cam 215. As illustratedin FIG. 5, the upper end of the switch actuating lever 212 is formedwith a forwardly extending shaft portion 270 which is received by anaperture 272 which is formed in the plural position lever 268. Aconventional pivot 274 may be provided for generally centrallysupporting the plural position lever 268, and the right portion of theplural position lever may be provided with a forwardly extending tab 276for riding on the surface of the ON- OFF-SLEEP cam 215.

In order to insure continuous following contact of the tab 276 with thesurface of the cam 215, a spring 278 may be stretched between a tab 280which is formed on the plural position lever and a tab or otherprojection 282 which may be struck from the lower portion of themounting plate 100. With this arrangement, the spring 278 willconstantly urge the right portion of the plural position lever 268downwardly as viewed in FIG. 5.

With further reference to FIG. 5, it can also be appreciated that uponrotational movement of the sleep cam 215 to lift the tab 276, the rightportion of the lever 268 will be moved upwardly and the left portion ofthe lever 268 will be moved downwardly to change the position of switchactuating lever 212 with respect to the switch blade 202 and also to theend of shaft 242.

The ON-OFF-SLEEP cam 215 may be rotated at any time to close the switchwithout disturbing the position of the alarm time cam shaft 242. Forexample, should it be desired -to close the switch 206, 208 after theWAKE-NO WAKE alarm shut-off cam 216 has moved the switch to the positionillustrated in FIG. 3, it is merely necessary to rotate the SLEEP-ON-OFF cam to move the switch actuating lever 212 longitudinally downwardlyfrom the position illustrated in FIG. 3 to the position illustrated inFIG. 6. During this movement, the end of the alarm time cam shaft 242will slide from an intermediate forward surface 221 of the switchactuating lever to a more rearward intermediate surface 284 of theswitch actuating lever thereby pivoting the lever 212 forwardly to moveblade 202 forwardly to close switch contacts 206, 208. In addition,during this same movement the forward portion of the switch blade 202will have merely slid somewhat upwardly on the lower end portion 217 ofthe switch actuating lever 212, but not high enough to move to. therearward in terrnediate portion 284. Thus, during such downward movementof the switch actuating lever 212 by the ON- OFF-SLEEP cam, the switchwill be moved from its opened position illustrated in FIG. 3 to itsclosed position illustrated in FIG. 6 and the switch actuating lever 212will have been effectively. removed from the rear surface of shaft 242to permit the resilient switch blade described is illustratedand'described in greater detail in our co-pending application, Ser. No:241,965, filed Apr. 7, 1972. i

The sleep cam portion 298, 302 of our unique ON- OFF-SLEEP cam 215 alsooperates the plural position lever 268 and the elongated switchactuating lever 212. This sleep mechanism is provided for manuallymoving the switch 206, 208 to a closed position and automaticallymaintaining the switch in the closed position for a preselectedadjustable time interval. Such a mechanism is particularly useful forturning off a radio receiver in the evening after a person has gone tosleep, and thus, mechanisms that accomplish this function have beencalled a SLEEP switch.

In the embodiment illustrated in FIG. 6, the SLEEP portion of cam 215includes a generally smooth raised cam surface 302 for cooperating withtab 276 for holding the switch 206, 208 in a closed or radio on positionfor a preselected time interval. Ratchet teeth 298 are formed on the cam215 for incrementally driving the gear and the sleep cam surface 302 ina clockwise direction as a function of time. At the end of thepreselected time interval the gear 215 will have been rotated to aposition wherein tab 276 is moved from the smooth raised sleep surface296 into an off notch 294 SLEEP CAM DRIVE In accordance with ourinvention a unique pawl and ratchet mechanism is provided for drivingthe sleep switch cam 215. With this mechanism, whenever the ratchettoothed portion 298 of the sleep cam is rotated to the positionillustrated in FIG. 8 the pawl lever 300 will rotate the sleep cam oneincremental movement every minutes.

The overall shape of the SLEEP-ON-OFF cam may be readily observed inFIGS. 5, 6 and the other FIGS. of the application, and in view of theforegoing description it can be appreciated that it performs a pluralityof functions. In the preferred embodiment, the entire cam 215 includingthe ratchet toothed portion 298, a shaft portion 304, an OFF notch 294,a raised ON notch 301, and SLEEP surface 302 are all integrally formedon a single molded part.

Should an operator grasp shaft knob 304 and rotate the cam 215 clockwisefrom its off position to its ON position the tab 276 will be lifted fromthe OFF notch 294 and placed within the ON notch 301 on the uppersurface of the cam. In this position the switch will be closed as shownin FIG. 6. However, the sleep drive lever 300 will be placed in thevicinity of a smooth nontoothed portion 306 of the sleep cam 215, andthus, movement of the sleep drive lever will have no effect on the sleepcam and the switch will remain in its closed position until the cam 215is manually rotated to position the tab 276 on the sleep surface 302 orin the OFF notch 294.

Should the ON-OFF-SLEEP cam be moved in a clockwise direction from itsoff position illustrated in FIG. 4 to place the tab 276 on the generallysmooth peripheral surface 296 of the sleep cam, the switch will beplaced in its closed position illustrated in FIG. 6 and the gear portion298 of the sleep cam will be placed in a position to be actuated by thesleep drive lever 300. In this position, the sleep drive lever willincrementally move the sleep cam to eventually move the tab 276 to theoff notch at the end of the preset sleep interval, as shown in FIG. 3.

In accordance with our invention the pawl and ratchet mechanism 300, 298is uniquely designed and combined with a units cam 52 and a drive lever86 of -the digital clock disclosed in our aforementioned copendingapplication, Ser. No. 196,479, filed Nov. 8, 1971, for indexing thesleep switch cam 215 one increment every 5 minutes when the cam 215 isrotated to any one of its SLEEP positions illustrated in FIG. 1. Toachieve this, the sleep pawl lever 300 is pivotally mounted on the drivelever 86 and is counterweighted at 303 for urging a pawl 305 upwardlyinto contact with the sleep cam 215. With reference'to FIG. 2 and theMinutes and Tens of Minutes Cam Indexing and Drive Arrangement it can beappreciated that the drive lever 86 is provided with cam surfaces forcooperating with an eccentric drive roller 106 to move the drive lever86 and a units cam pawl lever 84 one incremental movement every minute.Moreover, it can be seen that the actuating movement for the units cam52 occurs when the drive lever 86 is moved to the right as shown in FIG.2. In accordance with our invention the sleep cam actuating movementthrough pawl lever 300 occurs when the lever 86 is moved to the left asshown in FIG. 2. Thus, with the parts in the position illustrated inFIG. 8, movement of the drive lever 86 counterclockwise to the leftaboutpivot 88 will move the entire pawl lever 300 to the left to move thesleep cam 215 one increment in a clockwise direction. With thisconstruction, the actuating movement for the sleep cam 215 does notoccur at the same instant as the actuating movement for the minutes cam52, and thus, the motor load at any particular instant is minimized.With particular reference to FIG. 2, it can also be appreciated that thesleep ratchet drive pawl 300 is mounted on a pivot pin 307 which ispositioned closer to the drive lever pivot 88 than pawl lever 84 becauseonly a short stroke is required for moving the sleep cam one increment.

The pawl drive lever 300 is also uniquely combined with the previouslydescribed digital clock structure for indexing the sleep cam 215 anynumber of increments during a ten minute period. In the preferredembodiment illustrated in FIG. 8, a shaft 322 which extends rearwardlyfrom the units cam 52 is provided with two flat surfaces 324 and 326 forpermitting the pawl 305 to move into engagement with the teeth on thesleep cam 215 only twice for each revolution of the units cam 52 ,oronce every 5 minutes. It can be readily understood that the units cam 52is rotatedat one revolution every ten minutes for displaying numeralsfrom 0 thru 9. Thus, two flat surfaces will provide an incrementalmovement every 5 minutes, and the number of flat surfaces on the camshaft 322 could be selected for achieving any desired number ofincremental movements of the sleep cam 215.

As shown in FIG. 8 an upper surface of the pawl lever 300 is arrangedgenerally parallel to the flat surface 326 of the shaft 322, andtherefore, the counterweight 303 of the pawl 300 is effective to movethe pawl 305 into engagement with the teeth of the sleep cam 215. It canbe seen that when the shaft 322 is moved approximately 36 from the FIG.8 to the FIG. 9

position during a next succeeding incremental movement of the units cam52, the shaft 322 will hold the pawl in its lower position as shown inFIG. 9 to thereby hold the pawl 305 away from the ratchet teeth of thesleep cam during the next succeeding movements of the drive lever 86.

' With particular reference to FIGS. 2, 8 and 9, it can be appreciatedthat the units cam may be readily molded from a piece of plastic toprovide all of the cam and tooth surfaces illustrated, and naturally,the surfaces 324 and 326 on shaft 322 may be also provided during themolding operation of the units cam 52.

OPERATION If at bed time it is desired to have the switch for operatingapparatus such as a radio receiver closed to turn the radio on for ashort time interval before falling asleep, the sleep cam knob 304 isrotated in a clockwise direction to position the tab 276 on the smoothcam surface 302 of the sleep cam. As shown in FIG. 1, any desired sleeptime interval up to three hours may be selected.

The mechanism can now operate to drive the tab 276 along the smoothsurface 296 of the sleep cam for the desired sleep time interval atwhich time the tab 276 will snap into the off notch 294 to thereby liftswitch actuating lever 212 from the position illustrated in FIG. 6 tothe position illustrated in FIG. 3.

From the foregoing discussion it can be appreciated that our uniquesleep cam indexing mechanism may be readily formed and added to anyalarm clock timer and particularly the digital'alarm clock timerdisclosed in our prior co-pending application Ser. No. 196,479, filedNov. 8, l97l. Relatively few additional parts are required. It is merelynecessary to pivot a pawl lever 300 on the drive lever 86 which is alsousedfor indexing and driving the units and tens display indicators ofthe digital clock. Moreover, the pawl lever 300 is pivoted to-the drivelever at such a location. that it drives the ratchet of the sleep cam onthe return stroke of the drive lever to thereby minimize motor load.Thus, when the motor is being utilized for driving the units and tensdisplay indicators it is not rotating the sleep cam 215, and conversely,when the drive lever 86 is being utilized for driving pawl 300 to rotatesleep cam 215 the display indicators are not being indexed. Accordingly,a unique sleep cam mechanism which does not significantly add to thetorque requirements of the motor is achieved.

What we claim is:

1. In an alarm clock timer mechanism the improvement comprising:

a. a switch having an open and a closed position;

b. a timing motor;

c. a sleep cam operably connected to said switch for closing said switchfor a predetermined time interval;

d. manual means connected to said sleep cam for moving said sleep cam toopen or close said switch;

e. ratchet teeth formed on said sleep cam for permitting said sleep camto be moved from a switch closed position to a switch open position bysaid timing motor;

f. a pawl lever having a pawl positioned in said alarm clock timermechanism;

g. means for moving said pawl lever to movesaid pawl into engagementwith said ratchet teeth; and

h. a drive mechanism operably connected to said timing motor for movingsaid pawl lever and said pawl back and forth to incrementally move saidsleep cam as a function of time to thereby open said switch at the endof said time interval.

2. An alarm clock timer mechanism as defined in claim 1 wherein thesleep cam is rotatably mounted in the alarm clock timer and includes acam surface for operating the switch and a ratchet tooth surfacepositioned in front of the cam surface for cooperating with the pawllever to rotate the sleep cam as a function of time to open the switch.

3. An alarmclock timer as defined in claim 2 wherein said ratchet teethextend through a sector of the sleep cam with an adjoining sector of thesleep cam being a smooth curved surface so that should said pawl leverbe positioned on said smooth surface no actuating movement of the sleepcam will occur.

4. An alarm clock timer mechanism as defined in claim 1 wherein:

a. a plural position lever having two arms is pivotally mounted on saidclock timer;

b. a'switch actuating lever is connected to one of the arms pluralposition lever;

c. said sleep cam being positioned adjacent to the other arm of theplural position lever; and i said manually rotatable sleep cam includesa lower cam surface for moving said plural position lever to open theswitch, a raised notched surface for holding the plural position leverin one position to hold the switch open and a raised curved generallysmooth cam surface for locating the plural position lever to hold theswitch in a closed position for a predetermined sleep time interval.

5. An alarm clock timer as defined in claim 1 wherein a clock cam havinga flat surface is rotated adjacent to the pawl lever for holding thepawl lever out of engagement with the ratchet teeth of the sleep cam topermit the pawl to drive the sleep cam only once during a number ofconsecutive to and fro movements of the pawl lever.

6. An alarm clock timer mechanism as defined in claim 1 wherein the pawllever is counterweighted for urging the pawl toward said ratchet teeth.

7. An alarm clock timer mechanism comprising:

a. two display indicators for visually displaying numerals from 0 thru 9to indicate minutes and tens of minutes;

b. a rotatable units cam for progressively actuating the minutes displayindicator to display numerals from 0 thru 9 to indicate minutes; I

c. a rotatable tens cam spaced from the units cam for progressivelyactuating the tens of minutes display indicator for displaying numeralsto the left of the units numerals in order to display tens of minutes;

d. a supporting means for rotatably supportingsaid units and tens camsas axes generally parallel to each other and spaced from each other;

e. a drive lever pivotally mounted on said supporting means between saidunits and tens carns, said lever having a drive strokeand a returnstroke;

f. a first pawl lever having a central portion and two side portions,the central portion -of said pawl lever being pivotally mounted on saiddrive lever, said pawl lever having a pawl formed in one of its sideflat cam surfaces for permitting said second pawl lever to be moved intoengagement with said sleep cam only twice for each revolution of theunits cam whereby said second pawl lever may move said sleep cam onceevery five minutes.

9. A digital alarm clock timer as defined in claim 7 wherein said secondpawl lever is counterweighted for urging said second pawl lever towardsaid units cam and toward said sleep cam.

1. In an alarm clock timer mechanism the improvement comprising: a. aswitch having an open and a closed position; b. a timing motor; c. asleep cam operably connected to said switch for closing said switch fora predetermined time interval; d. manual means connected to said sleepcam for moving said sleep cam to open or close said switch; e. ratchetteeth formed on said sleep cam for permitting said sleep cam to be movedfrom a switch closed position to a switch open position by said timingmotor; f. a pawl lever having a pawl positioned in said alarm clocktimer mechanism; g. means for moving said pawl lever to move said pawlinto engagement with said ratchet teeth; and h. a drive mechanismoperably connected to said timing motor for moving said pawl lever andsaid pawl back and forth to incrementally move said sleep cam as afunction of time to thereby open said switch at the end of said timeinterval.
 2. An alarm clock timer mechanism as defined in claim 1wherein the sleep cam is rotatably mounted in the alarm clock timer andincludes a cam surface for operating the switch and a ratchet toothsurface positioned in front of the cam surface for cooperating with thepawl lever to rotate the sleep cam as a function of time to open theswitch.
 3. An alarm clock timer as defined in claim 2 wherein saidratchet teeth extend through a sector of the sleep cam with an adjoiningsector of the sleep cam being a smooth curved surface so that shouldsaid pawl lever be positioned on said smooth surface no actuatingmovement of the sleep cam will occur.
 4. An alarm clock timer mechanismas defined in claim 1 wherein: a. a plural position lever having twoarms is pivotally mounted on said clock timer; b. a switch actuatinglever is connected to one of the arms plural position lever; c. saidsleep cam being positioned adjacent to the other arm of the pluralposition lever; and d. said manually rotatable sleep cam includes alower cam surface for moving said plural position lever to open theswitch, a raised notched surface for holding the plural position leverin one position to hold the switch open and a raised curved generallysmooth cam surface for locating the plural position lever to hold theswitch in a closed position for a predetermined sleep time interval. 5.An alarm clock timer as defined in claim 1 wherein a clock cam having aflat surface is rotated adjacent to the pawl lever for holding the pawllever out of engagement with the ratchet teeth of the sleep cam topermit the pawl to drive the sleep cam only once during a number ofconsecutive to and fro movements of the pawl lever.
 6. An alarm clocktimer mechanism as defined in claim 1 wherein the pawl lever iscounterweighted for urging the pawl toward said ratchet teeth.
 7. Analarm clock timer mechanism comprising: a. two display indicators forvisually displaying numerals from 0 thru 9 to indicate minutes and tensof minutes; b. a rotatable units cam for progressively actuating theminutes display indicator to display numerals from 0 thru 9 to indicateminutes; c. a rotatable tens cam spaced from the units cam forprogressively actuating the tens of minutes display indicator fordisplaying numerals to the left of the uniTs numerals in order todisplay tens of minutes; on d. a supporting means for rotatablysupporting said units and tens cams as axes generally parallel to eachother and spaced from each other; e. a drive lever pivotally mounted onsaid supporting means between said units and tens cams, said leverhaving a drive stroke and a return stroke; f. a first pawl lever havinga central portion and two side portions, the central portion of saidpawl lever being pivotally mounted on said drive lever, said pawl leverhaving a pawl formed in one of its side portions for engaging the unitscam for moving the units cam one increment each minute on the drivestroke of said drive lever; g. a switch having an open and a closedposition; h. a sleep cam for moving said switch from a closed to an openposition as a function of time; and i. a second pawl lever pivotallymounted on said drive lever for moving said sleep cam one increment onthe return stroke of said drive lever.
 8. An alarm clock timer mechanismas defined in claim 7 wherein said rotatable units cam includes two flatcam surfaces for permitting said second pawl lever to be moved intoengagement with said sleep cam only twice for each revolution of theunits cam whereby said second pawl lever may move said sleep cam onceevery five minutes.
 9. A digital alarm clock timer as defined in claim 7wherein said second pawl lever is counterweighted for urging said secondpawl lever toward said units cam and toward said sleep cam.